The block has a two-piece rear seal, timing cover is a stock sbc painted black, the first pan was a stock Chevy pan and I used the 4-piece cork and rubber gaskets, and the second one is the pan that has a skid plate welded to it. It requires the thicker gasket which I used (Fel-Pro, I think). I chose the one-piece gasket because it came highly recommended by guys on other forums. They reported no leaks using one.